Art of treating metal work



P 1935. H. ROSENBERG ART OF TREATING METAL WORK Filed Sept. 24, 1929 2 Sheets-Sheet 1 HEYMAN R05 ENBERQ,

Sept. 10, 1935. H. ROSENBERG ART OF TREATING METAL WORK gnucnioz: HEYMAN RUSENBERL, 3, @fll 2 Sheets-Sheet 2 Filed Sept. 24, 1929 m. m E

hi5 dffotuu Patented Sept. 10, 1935 UNITED STATES PATENT OFFIC 13 Claims.

This invention relates to improvements in the art of hardening metal work, and more particularly to the art of heat treating the work and of quenching the same.

The primary object in view is the production of hardened metal work of uniformly high standard, and a more detailed object is the effective treatment of articles of work in groups in a manner substantially equalling individual treatment of such articles.

A still more detailed object is the heat treating of masses of articles of work so conditioned as to largely obviate the delay commonly incident to penetration of the mass, whereby each article of the mass is caused to receive substantially identical treatment with every other article; and a corollary object is the chilling of each article of a mass of articles as an individual article as distinguished from mass treatment.

In the carrying out of the invention any of many forms of apparatus may be utilized, and it should be understood that while the treatment of small articles is particularly had in mind, that term must be accepted relatively, and wherever a number of articles may be grouped into a mass capable of treatment as unit, such articles and such treatment are within the purview of the present invention; and, also, while the primary intent of the present invention is for case-hardening of the work being treated, complete penetration and therefore full hardening is well within the scope, intent, and purpose of the present invention.

It has heretofore been the practice to heat a relatively large mass of comparatively small articles of work to the requisite high temperature, as, for instance, in a molten salts bath (such as cyanide) and to remove the mass and discharge the same as a mass into a quenching vat. I have improved this mode of procedure as set forth in my co-pending application Serial No. 372,457 (patented December 30, 1930, Patent No. 1,786,508) in various ways, including the maintenance of the mass under the heat action while being transported to the quenching bath, and also including maintaining the bath at a substantially uniformly low temperature by circulation or replacement of the quenching fluid and also removal of the quenched work in the form of a mass without appreciable disturbance of the quenching bath. Reference may, therefore, be had to my said patent for structural details. And, I have also improved the prior state of the art as first above indicated by utilizing the same furnace and preferably the waste heat thereof as a source of heat; for preheating articles of work to be hardened, as fully set forth in my copending application Serial No. 380,350, to which reference may be had for structural details. It should be understood that while the accompany- 5 ing drawings do not disclose some of the details of the last-named, co-pending application, such details may well be used in the preceding steps leading up to the present invention.

In the carrying out of the present invention, 10 a mass or masses of relatively small articles of work is or are arranged to have such thickness or otherwise dimensioned with respect to the mass as to afford substantially instantaneous accessibility without the delay required for penetration 15 of relatively large masses having excessive thickness. The thus-conditioned mass of small articles is raised to the requisite temperature by the action of molten salts in which the mass is submerged, or otherwise as preferred, and then the mass while maintained subject to the heat action is discharged toward a body of quenching fluid, but instead of entering the fluid as a mass, whereby the chilling action may be delayed incident to penetration to the interior of the mass, the mass is separated or segregated into individual units of one article each, and each separate article is quenched distinctively from the balance, so that the whole process of hardening is carried out in fact en masse, but in result as if a single individual article were alone being treated. This art or mode of treatment may, of course, be carried out by any of numerous forms of apparatus, one preferred form being illustrated in the ac companying drawings in which 5 Figure 1 is a view in side elevation, parts being broken away and seen in section for disclosing interior structure.

Figure 2 is a top plan view with the cover housing or hooding removed and parts of the circulatory system broken away for the saving of space.

A specific statement of an illustrative succession of steps comprehending a complete embodi ment of the preferred mode of the present improved art will most readily be understood by reference to the details of the structure shown in the accompanying drawings, and for that reason such structure will be briefly set forth specifically.

Referring to the drawings by numerals, I indicates a furnace heated from any appropriate source, such as the use of gas as the preferred fuel. A cover plate 2 closes the top of furnace I and is provided with a central aperture through which depends the vat 3 adapted for containing the cyanide or other treating salts. Journaled preferably to the frame of furnace I at one side thereof or to the top plate 2 in any appropriate manner is a rock shaft 4 to which is rigidly fixed a crank'arm 5. As illustrated, the crank arm 5 assumes the form of a plate, the free end portion of which carries the work container to be immersed in the molten mass in vat 3. Such work container may assume any of numerous forms, each of which should be such as to cause the mass of work to be retained in the form of a relatively thin body whether as a continuous layer or individual groups. Such container may be a comparatively thin reticulated ring-like or annular body, as, for instance, made up of concentric spaced walls and a bottom in the form. of an annulus, the parts being proportioned to be susceptible of immersion in the vat 3. However, I prefer, instead of such continuous container ring, to provide a series of individual baskets 6, 6. Plate 5 is formed with an aperture for each basket 6, and each basket is flanged at its upper or open end to overhang the plate 5 while the body of the basket extends through and beyond the plate or arm 5. Appropriately movable and detachable buttons I, I, engage the upper ends of baskets 6 and clamp the baskets rigidly in engagement with plate 5, each button I being retained by a bolt 8 detachably threaded into plate 5. As will be clear from Figure 2, the baskets 6 are arranged to encircle the central area of vat 3, and a larger or smaller number or group of baskets 6 may be utilized as preferred, it being essential that each basket 6 be of such dimension that the mass of articles of work which it may contain will be of sufficiently thin thickness to afford substantially instantaneous access of the molten salt to each article of work in the mass when the basket is introduced into the molten salt. A greater cross sectional dimension of a basket 6 would defeat the purpose of the present invention so far as the feature of heat treatment is concerned and would be a step backward toward the method heretofore proposed in which only a single, large basket is employed practically filling the salts vat.

Shaft 4 is preferably provided with a counterbalance 9 and with gearing III, III, having an operating handle II to facilitate oscillation of shaft 4 and consequent swinging of the plate or crank arm 5 to and from the full line position of Figure 1.

Adjacent the furnace I is arranged a quenching vat I2, which is supplied with quenching fluid through a pipe I3, and appropriate overflow I4 being connected with vat I2 for the drawing off of heated or excess quenching fluid. If water is being used as the quenching fluid, the pipe I3 will lead from the city main or other water supply, and the drain I4 will lead to the sewer I5, or other waste pipe; but if oil or other more valuable quenching fluid is being used, a circulatory system will be employed wherein the pipe I3 will lead from the source of supply and the pipes I4 and I5 will return to such source, an appropriate circulatory pump (not illustrated) being utilized to maintain sufficient circulation to keep the temperature in vat I2 at the required low degree. Beyond the vat I2 is preferably arranged an appropriate frame in which is mounted a suitable hopper IE to receive finished work and to deliver the same to any appropriate point of disposal, such as a container I'I.

At that side of vat I2 at which the hopper I6 is located, a shaft I 8 is iournaled having an operating handle I9, and to the shaft I3 is flxed a preferably parti-globular, reticulated basket 20 proportioned to have its upper or open end occupy substantially the entire open upper end of vat I2 when the basket 20 is in the vat. Upstanding standards 2 I, 2I extend from the frame of basket 20 and carry a. cross bar 22 located to be struck by the free end portion of crank arm 5 when the crank arm is moved to the discharging position for limiting the extent of such discharging movement, and also to facilitate jarring the haskets 6 to dislodge therefrom articles of work which might otherwise remain in the baskets incident to being caught in some of the apertures of the walls thereof.

A baiiie apparatus is arranged to extend across and occupy substantially the entire area of the otherwise open, upper end of basket 20, and consists essentialy of side plates 23, 23, and cross baIlIe plates 24, 24, the latter plates being arranged, as seen in Figure 1, diagonally, so that the upper edge of each plate will overlap the lower edge of the next succeeding plate and yet leave a clear passageway between the two, each such passageway being inclined in a direction away from the furnace I or source of heat, whereby any splashing action occurring incident to work falling into the quenching liquid will be restricted against being expressed in a direction toward the vat 3. Also, the mass of work striking the baffles 24 will thereby be caused to separate into spaced, individual articles, each of which falls as a distinctive unit into the quenching liquid and receives its individual treatment a: distinctively as if it had not just previously been a part of a mass. The baffle apparatus made up of plates 23 and 24 is preferably detachably,

pivoted, as by removable bolts 25, 25, to the upper portion of the frame of baskets 20 at the forward part thereof, that is, at the point nearer furnace 1. Laterally-extending brackets 26, 26 outstand from the said baiiie apparatus in position to overhang the upper portion of the frame of baskets 20 and to thereby sustain the battle structure in a horizontal position above the basket when the basket 20 is in its receiving position within vat I2.

In the operation of the apparatus described and the carrying out of the details of one preferred succession of steps of the present improved art, the baskets 6 are supplied each with a batch of work, and the salt in vat 3 having been raised to the molten temperature, the baskets 6 are lowered into such molten salt by the turning of the handle II in the required direction. As the work enters the molten salt, the mass of work being of requisite, relatively thin, cross sectional thickness oflers practically no resistance to the free admission of molten salt which thus flnds access to the interior articles of work with practically the same facility as the approach of the salt to the outer articles of work. The work is left in the molten salt while the heat is continued to be supplied to vat 3 until the required high temperature of the work in the baskets 6 has been reached. This fact is preferably determined by a pyrometer including a thermocouple extending into the salt in vat 3 through a central aperture 21 formed through the plate 5. "It is well understood that the molten salt in vat 3 is maintained as nearly as may be at the required high temperature, but the introduction of each new load of work lowers the temperature until the new load of work has been raised to the required temperature, so that the work must remain in the vat 3 an appreciable time for the heat and salts treatment. When the pyrometer indicates that the requisite temperature has been reached, the operator will rotate the handle II and shaft III for swinging arm 5 from the full line position-of Figure 1 to the dotted line position thereof. As the baskets 6, thus move through a vertical arc to an inverted position, the batches of work in said baskets fall therefrom and strike upon the bafiie 23, 24, and are separated into individual articles of work which descend separately into the quenching liquid and are quenched to a uniform, high standard and quality of excellence and hardness. The fact that the batches of work are separated into individual articles tends to reduce the otherwise propensity to produce splashing of the quenching liquid, and the comparatively small resulting splashing incident to the falling of individual articles of work is largely suppressed by the plates 24 and wholly suppressed so far as movement in the direction toward vat 3 is concerned. As soon as the work has been discharged, the handle II is operated to effect reverse rotation of shaft 4, and return arm 5 to re-introduce the baskets 6 into vat 3. The baskets 6 may be loaded with work just before being ice-introduced into the vat, or after reaching a position within the vat. While the temperature of the work in the baskets 6 of the newly supplied batches is being raised, the operator will rotate the shaft I8 to swing the baskets 20 outward to the dotted line position seen in Figure l for discharging the quenched work into the hopper I6. An appropriate counterbalance 28 is preferably connected to shaft I8 to render this operation comparatively easy. As the basket 20 is being swung to the discharging position shown in dotted lines in Figure l, the baffle 2324 will swing upon its pivots 25 to an open position, being limited in the opening movement by contacting with the cross bar 22. It will be observed that as the basket 20 is being swung upward and out of vat I2, the work in the basket will naturally fall along the bottom of the basket toward that side connected to shaft I8, so that the open space left clear by the downwardly swung baffle is the space through which most or all of the discharging load of work will descend into hopper I6.

It is, of course, preferable to hood the work both for the. conservation of heat and the avoidance of dissemination of fumes into the atmosphere about the place, and such hooding may be and preferably is of the form set forth in my above-mentioned Patent No. 1,786,508, modified when desired by the additions shown in my copending application Serial No. 380,350.

The form of hooding preferred is shown in Figure 1 of the drawings as consisting of a hood 29 surmounting furnace I, a hood 3!] surmounting vat I2, and a vestibule hood 3| connecting the hoods 29 and 30. Hoods 29 and 30, are preferably vented, at 32, 32, and a tunnel-like guideway 33 is preferably extended from the hood 29 through vestibule hood 3I into hood and shaped to snugly permit passage of plate or arm 5 and the parts carried thereby, so that, while the said plate is in the tunnel 33, moisture cannot find access backward toward the vat 3 from vat I2. This tunnel construction is valuable in preventing excess return movement of vapors from vat I2 through the baffle 23-24 prevents back splashing. A gravity-closed door 34 provides that wall of hood 30 nearest hopper I6 and is pivoted at 35 to facilitate swinging, as indicated in dotted lines in Figure l, for enabling the discharge action and return of basket 20 while remaining closed automatically at all other times. Any appropriate access opening and closing doors therefore may be provided for hoods 29 and 33, 5 as, for example, a door 36 may be arranged in hood.29 and a door 31 in hood 30, each having appropriate hinge connections with its respec-- tive hood and having acceptable locking means, such as a latch 38, for normally retaining the 10 respective door against accidental opening. Each door 36, 31 is also preferably provided with a transparent plate 39 of any appropriate material, such as pyrex or mica, for enabling the operator to observe the action occuring within the hood [5 without allowing escape of vapors therefrom. The hoods 29, 30 and 3d and connected parts serve also as further assurance of the continued subjection of the articles of work in baskets 6 to the action of the heat of furnace I as the bas- 20 kets 6 leave the vat 3 and continuously thereafter until the work is actually discharged into the vat I2, so that at no time is the work being treated offered an opportunity for chilling or other reduction in temperature or cooling off 25 prior to the quenching action.

What is claimed is:

1. In the art of heat treating articles of metal work in bulk, grouping a mass of work articles into relatively thin thickness of bulk of such ar- 0 ticles, and subjecting the mass so grouped to the action of heat while maintaining the mass of such relativcly thin thickness as to afford substantially uniform and direct action of the heat on each individual article, discharging said mass 33 into a quench. and separating the articles of the mass during such discharging movement to cause them to enter ithe quench as spaced individual articles.

2. In the art of heat treating articles of metal 40 work in bulk, grouping a mass of work articles into relatively thin thickness of such articles, and subjecting the mass so grouped to the action of molten salt while maintaining the mass of such relatively thin thickness as to afford substantially uniform and direct action of the molten salt on each individual article, discharging said mass into a quench, and separating the articles of the mass during such discharging movement to cause them to enter the quench as spaced individual articles.

3. In the art of hardening metal work, raising the temperature of articles of work arranged en masse until each individual article has reached the requisite high temperature, and quenching each individual article of work separately from the mass.

4. In the art of hardening metal work, raising the temperature of articles of work arranged en masse until each individual article has reached 0 the requisite high temperature, and quenching each individual article of work separately from the mass while substantially maintaining the articles of work against lowering of the temperature thereof between the heating and the quench- 05 mg.

5. In the art of hardening metal work, raising the temperature of articles of work arranged en masse until each individual article has reached the requisite high temperature, discharging the mass of articles of work toward a body of quenching liquid, separating the individual articles of work from the mass prior to entering the quenching liquid, and introducing such articles separately into the quenching liquid.

6. In the art of hardening metal work, raising the temperature of articles of work arranged en masse by substantially direct heat action on each article, discharging the articles of work en masse toward a body of quenching fluid, segregating the articles of work from the mass as the-same approach the body of fluid, and introducing said articles of work separately from the mass into the quenching fluid.

7. In the art of hardening metal work, raising the temperature of articles of work arranged en masse by substantially direct heat action on each article, discharging the articles of work en masse toward a body of quenching fluid, segregating the articles of work from the mass as the same approach the body of fluid, introducing said articles of work separately from the mass into the quenching fluid, and maintaining the articles of work substantially against lowering of temperature until quenched.

8. The art of case-hardening metal work comprising raising the work to the requisite high temperature in a molten salt bath, elevating the work above the bath and allowing adhering material of the bath to drain back from the work while retaining the work in position with respect to the source of heat for substantially maintaining the attained high temperature thereof, and quenching the work substantially at such temperature.

9. In the art of heat treating articles of metal work in bulk, subjecting a group of such articles in mass arrangement to the action of heat for the required time period at the requisite temperature for the desired treatment, and thereafter separating the articles from the mass arrangement and, in thus separated condition, quenching the articles each individually independently of the others.

10. In the art of hardening metal work, raising the temperature of articles of work arranged en masse until each individual article has reached the requisite high temperature, and quenching each individual article of work separately from against any appreciable or substantial drop in temperature, and quenching each individual article of work separately from the mass.

12. In the art of heat treating articles of metal work in bulk, subjecting a group of such articles in mass arrangement to the action of heat for the required period at the requisite temperature for the desired treatment, thereafter separating the articles from the mass arangement for introduction into a quench, preserving the articles while en masse and while separated against any appreciable or substantial drop in temperature until quenched, and quenching the articles each individually independently of the others.

13. In the art of hardening metal work, subjecting each article of a mass of articles substantially into the direct action of heat and thereby raising the temperature of the articles to the requisite degree for hardening purposes, and quenching the articles of work individually, separately from the mass, the articles being preserved substantially against air cooling between the steps of heating and quenching.

HEYMAN ROSENBERG. 

